Percussive tool.



Patented Jan. 23, 1912.

2 SHEETS-SHEET 1.

A. G. GRICE.

PERCUSSIVE TOOL.

APPLICATION FILED 0M 5, 1909.

Patented Jan.23, 1912.

2 SHEETSBHEET 2.

UNITED STATES PATENT OFFICE.-

ARTHUR GEORGE GRICE, OF OARNOU 'S'IIE, SCOTLAND.

PEROUSSIVE TOOL.

the object being to produce a tool of this type which is economical to manufacture and is simple and efiicient in construction and action, and is particularly suitable for dressing stone although it may be used for other purposes.

The accompanying drawings illustrate several forms of percussite tool constructed tool.

according to the invention.

, Figure 1 is a sectional plan, andFig. 2 a sectional elevation illustrating one form of Fig. 3 is a sectional elevation illustrating another'form, while- Figs. 4 and '5 are respectively a sectional elevation and sectional plan illustrating a further form, the latter being taken on the .line A--B, Fig. 6, and the tool holder being omitted in Fig. 4 in order to illustrate certain de-- tails in its guide. Fig. 6 is a cross-sectional view taken on line CD, Fig. 4.

In one form of the invention a tool holder a having a removable head I) is adapted to slide in the end of a. cylindrical guide 0.

The latter is.provided with a socketd screwed upon its end and having a bore adapted to receive the neck 6 of the tool holder, the socket (1 being locked if desired by a screwed ring f. A spring 9 is interposed between t-he head I; and the socket (l for a purpose hereinafter referred to. The

uide c is secured at the other end to a casmg I]. which is made in two halves in order to facilitate the assembling of the mechanism contained within it, the two halves being held together by pins or screws in any convenient manner. Within the casing 7L is a rotary'cam a which may have a single use but is preterably provided with tworises as indicated in the drawings. The cam i is mounted upon or formed integrally with a spindle is which can be rapidly rotated in any convenient manner for instance by means of a flexible shaft. A ring-shaped member I surrounds the cam z' and is provided wit-h a projection m adapted to be engaged by the cam. The latter is rotated in'a direction indicated by the arrow at and Specification of Letters Patent. Application filed October 5, 1909. Serial No. 521,137.

, Patented Jan. 23, 1912.

the rises of the cam and the projection m are of such form that when the cam is rotated the member Z is gradually moved in a direction away from the tool holder, but is then sharply released in; order that the member Z may be rapidly returned in a direction toward the tool holder by means of a spring. In the example shown this is effected by a spring o-surrounding a rod connected to the member Z and fitted with a hammer (1 adapted to strike the head 6 of the tool holder. Leather washers 16 are provided to soften, the impact of the member l. The spring 0, may be adjusted by rotating a threaded ring 17 adapted to engage pins 18 on a bush 19. The head 6 and the hammer 9 may be provided with anti-friction devices such as balls 2'. The casing 70. is preferably provided with a convenient handle .9.

In operation a chisel or other tool is placed in the tool holder at and the handle .9 1s grasped in the; hand of the operator. The spindle is is rapidly rotated with theresult that the cam if imparts a rapid vibratory motion to the liammer g which in turn imparts its force to the tool holder 1; and the chisel or other tool therein.

For some purposes it is desirable that the blow of the hammer upon the tool holder should be slightly cushioned, and it is for this purpose that the spring 9 is inserted between the head b of the tool holder and the socket d.. It is to be understood, however, that this cushioning device may be In the preferred form of the invention as illustrated in Figs. 4 and.5 the hammer 9 acts upon the tool, holder (1 in a similar manner to that described with reference to the form illustratedin Figs. 1 and 2, but a tension spring t is provided between the tool holder (1. and the hammer q. The spring may be conveniently formed with hooked ends IL respectively engaging a pin 1' and a pin w, the latter having a. head an engaging a shoulder 3 on thehammer q. The tool holder c is also providedwith a cross'pin z adapted to slide in slots 2 in the end of the cylindrical casing c, this, pin permitting longitudinal. movement. of the tool holder, but preventing rotation thereof.

a 5 The object of the spring-t is to impart a cushion this. blow. ThlS is of particular im-- portance in the dressing of stone. While it is desirable tov obtain this elasticity or to slightly cushion the blow it is also desirable that the device employed for thispurpose should not lessen the effect of the'hammer upon the tool when'it first strikes the tool holder. By providing a spring such, as t the hammer q is free to first strike the tool holder a without any im ediment but after the latter has moved slig tly in relation to its guide 0 and beyond the limit of outward movement ofthe hammer q the spring tis tensioned, thus cushioning the blow of the tool upon the stone or other material operated upon. V

The spring 0 is adjusted by rotating the guide 0 within the sleeve 20 of the casing it, so that its threaded end 21 causes a threaded bush 19 to move axially on a squared land 22 clearly shown in Fig.6. To enab e the end of the guide 0 tobe inserted in the sleeve 20, the latter as well as the casin h is formed in two parts, held together lay the ring 23, and the bolt 25, and to facilitate turning 'the guide 0] and I outer connecting ring 23,are' rovided with leather knurled or other sur aces 24. In the last example described the cam i'is provided with four rises, but obviously the number of these rises may be varied as desired.

11 order that the -o erator may readily control the action of t e tool a pawl 3, is

ment with an inclined projection 4 on the member-Z in order that the latter may be moved backwardly so as to Withdraw itsfrom engagementwith the cam-- pro'ection V z w en the 001 is not required 'to operate. The awl 3 is conveniently mounted upon a spin e 5 fitted with a'lever 6 conveniently arranged for manipulation by the operator. The cam spindle k may be rotatedby a 5!; flexible shaft 7 terminating in a head-8 of squareor other angular section fitting within a correspondingly recessed socket 9 se-;. cured by a pinilO to the spindle 7c. The head" 8' is provided with a minded projection 11 ..dapted to bear again the end of the spindle is and the head is also rounded as ing adapted to be moved into and out of engage of adjustment of the shaft in relation to the spindle in one plane while the pin 10 permits of oscillation or adjustment in another plane at right angles thereto. Hemispheri- The spindle is is bearings 15..

. Having now described my invention'what I claim as new and desire to secure ters Patent 1s 1. A percusslve tool comprising in comby Let bination, a reciprocating tool holder, a guide therefor, a casing secured thereto, a rotary cam wwithm said casing, a member in engagement therewith said cam being adapted.

to intermittently move the member in a direction away from the tool holder and then to release it suddenly, a spring for returnmember and adapted on the return 'move-' ment of the latter to [strike the tool-holder and a tension spring secured to the tool holder and to the hammer, substantiallyas and for the purpose hereinbefore set forth.

2. A percussive tool comprising in combination, a reciprocating tool holder, a cylindrical guide therefor,-a casing secured to said guide 'andhaving a handle, a cam withsaid member in a direction toward the tool holder, a hammer connected to, said in said casing having a plurality. of rises,

a spindle for said cam, a ring-shaped member Surroundingsaid cam and having a pro-.

jection adapted to be engaged thereby, a

hammer, a rod connecting said hammer and the aforesald member, a return spring for said hammer and a tension spring connecting said hammer and the aforesaid tool holder, substantially as and for the purpose hereinbefore set forth. v

3. A percussive tool comprising in combination, a'reciprocating tool holder, a cylin drical guide therefor, a casingv secured to ide and having a handle, a cam withsaid in said casing having a plurality of rises, a spindle for said cam, ball bearings for said spindle, a ring-shaped member surrounding said cam and having a projection. adapted to be engaged thereby, a, hammer within the aforesaid guide, anti-friction devices upon the aforesaid tool holder and upon the hammer, a rod" connecting the hammer and the aforesaid member, a returnspring surroundin said rod, a tension sprlng connecting t e hammer and the tool :holder and means 'for preventing rotation of the tool holder, substantially as and for.

the purposes hereinbefore set forth.

4." A percussive tool comprising in combination, a reciprocating tool holder, a c'yling drical guide therefoiga. casing secured. to

said guide and having a handle, a'cam within said casing havinga plurality of:

rises,a spindle for said cam, a ring-shaped member surround ng said cam and havgng a projection adapted to. be engaged thereby, a hammer, a rod connecting said hammer and the aforesaid member, a return spring surrounding said rod, a tension spring connecting said hammer and the aforesaidtool holder, a pawl adapted to engagethe aforesaid member and a .lever for enabling the operator to oscillate said pawl for the-purpose of temporarily disengaging s'aidmemher from the cam, substantially as hereinbefore set forth. 1 v

'5. A percussive tool comprising in combi-- nation, a reciprocating tool holder, a cylin} drical guide therefor, va casing secured to said guide and having a handle, a camwithin sald casinghaving a plurality of rises,

a spindle for said cam, a ring shaped mem-g ber surrounding said cam and havlngaprojection adapted to be engaged thereby, a hammer, a' rod connecting said hammer and the aforesaid member, a return spring surroundingsaid rod, means for adjusting said'return spring, a tension spring" conv nectingsaid hammer and the aforesaid tool holder, a pawl adapted to engage the aforesaid member and a lever for enabling the Ifoperator to oscillate said pawl for the purpose of temporarily disenga ing said member from the cam, substantlally as herein- 

